What freedoms Belarus protects with their Constitution is much different than the actions of the Government.
While the rights to freedom of expression, access to information, and press freedom are nominally guaranteed by the Belarusian constitution, the country’s authoritarian government does not respect them in practice. Belarus has no independent judiciary or parliament to defend these freedoms.
https://freedomhouse.org/country/belarus/freedom-net/2024
Apple maintains no retail presence or support in Belarus and is also not registered as a content provider as seen in the link mentioned in your post. Due to that there are many options/features you will not have access to. The political environment does not bode well for Apple working with the Government to provide additional functionality. Another thing to be concerned about is if you loose access to the account signed into the device, you will not be able to remove the Activation Lock, leaving the device unusable.